Although some analysts believed that Apple's increased price tag for its nicest phone might drive customers away, that doesn't seem to be the case. Cook told CNBC that the iPhone X has been company's best-selling device every week it's been available, while the less expensive 8 and 8 Plus appeal to those who don't want to pony up $999 for a phone.

Basically, Thursday's earnings proved that Apple has the room to raise prices. Now the question for investors is how much higher they can go.